A device for identifying the air flow condition within a clothes dryer having a lint filter, an exhaust passage, and a blower is disclosed. The device includes a sensor, an input having a first end connected to the sensor and a free second end, wherein the free second end is adapted to be disposed within the clothes dryer, upstream from a filter, and wherein the sensor detects a differential between an operating pressure at the free second end of input versus a reference pressure to thereby determine whether a sufficient vacuum is present within the clothes dryer, and an output that provides an output characteristic based on the differential, wherein the output characteristic changes from a first characteristic to a second characteristic when the differential surpasses a differential threshold.